Lifting jack



Aug; 21, 1928-.

J. C. DAWLEY LIFTING JACK 2 Sweets-shew Filed Aug. 5, 1925 A. TTORNE YAug. 21, 1928. i 1,681,283

J. C. DAWLEY LI'FTING JAcK.

Filed Aug. 5, 1925 2 sheets-sheet ,2

1N VENroR Jcwas cyan/ey B Y I ATTORNEY Patented Aug. 2l, 1928.

UNITED s-TArEs PATENT omer.

JAMES c. DAWLEY, or DAYTON, oHIo. ASSIGNQR To THnJoYcEcmnLANn COMPANY,

4or nAY'roN, onro, A coR-Pomi'iroivk or oH-Io.

LIFTING JACK.

nppiicaeon med August 5, 1,925. serial No. 48,230.

This invention relates to lifting jacks and more particularly to what isknown as a self-lowering jack, in which the load moves downwardly underits own weight and its downward movement controlled by a fric tionbrake.

The main object of, the invention is to rovide im roved meansforcontrollingthe ibwering oi) the load, and to this end a furtherobject is to provide means for locking the friction devices in operativeposition so as to positively hold the load against down-` ward movement.

A further object of the invention is to provide an improved one-wayclutch for con# necting the lifting element with the brake.

A further object of the invention is to provide improved meansformounting the arms which actuate the friction members.

Other objects of the invention will appear as the device is described indetail.

In the accompanying drawings Fig. is a front elevation, partly insection, of a liftl ing jack embodying my invention; Fig.` 2 is asection taken on the line 2-2 vof, Fig. 1; Fig. 3 is a side elevation ofthe clutch, partly in section; Fig. 4 is a vertical section takenthrough the clutch of Fig. 8; Fig. 5 is an elevation of the supplementalhousing with the cover plate. removed to show the actuating device andVlock for thefriction members in elevation; and Fig. 6 is sectional viewshowing the actuatingA device and lock of Fig. `5 in plan. i

In these drawings I have illustrated one embodiment of the invention andhave shown the sameV as applied to a lifting jack of a type shown inPatent No. 1,344,117, granted June Q2,

but vit will be understood that this particular type of ack has beenchosen for the purpose of illustration only, that the controllingmechanism may be applied to jacks of vari- A ous kinds and may takevarious forms without departing from the spirit of the invention. p i

The jack as lieie shown comprises a base 1 having a hollow standard 2extending upwardly therefrom and provided at ,its up-` per end with anut 3 in which isthreaded av screw 4 constituting the lifting elementofthe ack. Rig-idly secured to the screw above the nut is a beveled gear 5on which is sup ported the load engaging cap 6, a ball bean beveled gear5.

1920 to Ripsch, Dawley and Derby,

ing 7 being preferably.interposed between the capand the gear. Rigidlysecured to and depending from the load engaging cap 6 is a housing Swhich embraces the standard y able bearings formed in the inner wall 12of the supplemental housing and in 4the partition 11 is a shaft 13 whichextends into the main housing and has mounted on its' inner end abeveled gear 14 which meshes with the The outer end of the shaft extendsbeyond the outer wallof the supplemei'ital housing and has rigidlysecured thereto a ratchet wheel 16 with which coope'rates' a -pawl 17carried by a` lever socket ,18 pivotally mounted on the end of theshaft. The manipulation of this lever will rotate the shaft 13 in thedirection to impart lifting movement to the lifting element.

The downward movement of the lifting element is normally prevented bysuitable cont-rolling devicesl of such a` character'that they will notinterfere with the elevation of the liftingeleinentzbut will normallynreveiit the downward movement thereof. Y his cont-rolliiig devicecoii'iprisesineans, however, for releasing the load to permit it to movedownwardly under its own weight, the lift- Rigidly secured to one sideof thek into two compartments. Journaled in suiting screw being of sucha pitch that-,it will run downward yund-er the weight of the nor.-

Amal load. In the present embodiment of the invention the controllingmechanism comprises a worm gear19 rotatably mounted on the shaft 13 andmeshing with a worm 20 secured to a shaftQ()a which extendstraiisversely to the shaft The worm 2O is connectedat its rear end witha brake shaft 21 to which is rigidly secured a` brake meinber or drum22. The connection between the worm and the brake shaft may be of anysuitable character and as here shown a,. worm gear 120 is connected withthe worm 2() A and meshes with a worm 121 on the brakeshaft The wormgear 19 being loosely mounted on the shaft 13 will notdinterfere Withthe rotation of that shaft during the elevation lll shaft when thelatter is rotated in a reverse direction by the downward movement of thelifting element.. In the present construction. this clutch comprises aratchet wheel 23 rigidly secured to the shaft 13 adjacent to the wormgear 19, this gear being here :ihown as provided with a. recess in itsouter face so that the periphery thereof partially overhangs the ratchetwheel. kRigidly secured to the worm gear, partially within the recesstherein, is a` pawl carrier or frame which, as here shown, comprises aninner annular f ame member or plate 24 which is rigidly secured to theweb of the worm gear by means of a series of studs 25 and 2G, cach 'ot'which is provided with a. collar 27 seated in a recessin the outer faceofthe annular plate 2l and has its inner end projecting through the webof the worm gear and upset or riveted to rigidly secure the samethereto. Each of the studs 25 and 2G project beyond the Vouter faceofthe annalar plate 24 and these studs form supports, respectively, forpawls'and springs. The inner member 24 of the pawl carrier has rigidlysecured thereto and preferably formed integral therewith a series ofabut ments 28 which extend across the ratchet wheel and to the outerends of which the outer member 29 ofthe pawl carrier is secured, thisouter member also being in the form of an annularl plate and being hereshown as secured to the abutments by screws $30. The several ahutments28 are spaced short distances in the rear of the respective studs 26 andeach abutment is provided in that edge adjacent to the correspondingstud with a curved recess 31,' the surface of which conformssubstantially with the are of a circle described about the axis of thestud. Mounted on each stud 26 is a pawl 32 havingl its ends shaped tolit within :he recess 31 of the adjacent abutment. The pawl is looselymounted on the stud, the opening therethrough being of greater diameterthan the diameter of the stud, so that the thrust on the pawl will beagainst the abutment and not` against the ustud. The studs 25 arearranged in the rear of the respective abutmentsQS and between the sameand the free endg of the succeeding pawls. Coiled about each of thesestuds 2,"3 is a spring having an end portion l projecting from one sidethereof and engaging the rear edge of the'adjacent abutment 28. Theother end portion'l of the spring projects 'rearwardly and engages thefree end of the succeeding pawl to press the,

same against the ratchet wheel. Each spring is coiled loosely about itsstud 2o so that when placed under tension the coils may contract, thuspermitting the veasv compression of the spring and avoiding theloealizing of the strains. Such a. construction permits the use of astrong spring but provides the same with a large degree of resiliencyand a corresponding ease of operation. Further, the arrangement enablesthe force to be applied to the pawl near the free end thereof where itwill be most etiectively utilized. Y

It will be apparent, therefore, that when the lifting element movesdownward the clutch will connect the worin gear with the shaft 13 andcause this worm gear to rotate. The pitch of the teeth on the worm gearand worm 20 is such that the worin gear will drive the worm and movementwill he transmitted from the worm shaft 2l to the brake member or drum22. Cooperating with this brake member is a friction device which may becaused to engage the brake member to prevent or retard its rotation.Preferably this friction device is' provided with parts which aremovable toward and from one another to control the action of thefriction device on the brake member. These movable parts may be arrangedin any suit` able relation to the friction device and, as here shown,are so arranged that their movemont one toward the other will canse thefriction device to operatively engage the brake member. The movableparts are acted upon by a yieldable device which tends normally to somove the parts as to cause the friction device to grip the brake memberbut which may be manually retracted to relieve the gripping action ofthe friction device to the desired extent. Associated with thisyieldable device are means for positively holding the friction device ingrippng engagement with the brake member and to thus lock the brakemember against movement.

The controlling devices for the friction device may take various formsland may he arranged in various positions with relation one to the other.In that form of inechanism here illustrated the friction device consistsof a single annular member or split ring 5l, the split side of which isarranged at the forward side. of the brake drum and is provided withforwardly extending lugs the outer edges of which are preferablytapered. The friction member is provided at its rear side with a recessto receive a fixed stud or pin 5G which centers the same with relationto the brake member. Slidably mounted within the housing 10 is a slideblock 57 which is here shown as mount-4 ed in a guideway 58 rigidlysecured to the partition 11 and which has in its rear end a taperedrecess 59 to receive the forward ends of the tapered parts or lugs 55 ofthe friction device. A spring acts on this slide block to vpress thesame rearwardly and cause the friction device to normally grip the brakemember. Preferably the slide block is provided with a forwardlyextending stem or shank 6() about which is coiled lll) lso

a spring 61 which is coniinedgbetween the side wall of the housing andthe slide block and tends to nieve that block rearwardly. The stem 60has a reduced portion which extends through an opening in the side wallof the housing and this reduced portion is here shown as a separate rod62 which is screw threaded into the stem G0 and providedon itsgouter endwith a' knob G3 by means of which the stem and slide block Vmay be drawnoutwardly against the action tive engagement with the brake drum.

While I have shown and describedl certain embodiments of'my invention Iwish it to be understood that Ido not desire to be limited to thedetails thereof as various modifications may occur to a person skilledin the art. r

Having now fully described my invention, whatV I claim as new and desireto secure by Letters Patent, is: i 1. In a lifting jack, the combinationwith a lifting element, means for actuating the same to lift the load, arotatable brake member, means foi' causing `said brake'member to berotated by the downward movement of said lifting element7 and a frictiondevice cooperating with said brake member to control tlie downwardmovement of said lifting element, of controlling mechanism comprisingseparately.operable means to normallyA control the action of saidfriction device and to positively retain said friction device 1n contactwith said brake member.

In a lifting jack, the combination with e a lifting element, means foractuatingthe same to lift the load, a rotatable brakemciubei', means forcausing said brake member to be rotat'd by the downward movement ofrsaid lif, ng element.` `and a friction device cooperating with saidVbrake member to control the downward movement of saidlifting` element,of controlling mechanism comprising manually operated means to normallycontrol the action of said friction device,.and a screw threaded memberto lockvsaidv fric tion device in contact with said brake member. i

3. In a lifting jack, the combination with a lifting element, `meansforactuatingthe same to lift the load,` a rotatable brake member, meansfor causing said -brake member to be rotatedV by` the downward movementYof said lifting element, and a friction device cooperating with saidbrake -member and comprising parts movable toward and from cach other tocontrol the contact between said friction device and said brake member,of a'. single vlocking member movable into engage'ment` with both ofsaid parts to lock said friction device in contact with said brakemember.

4. In a lifting jack, the combination with a lifting elenfieiit, meansfor actuating the same to lift the load, a rotatable brake meinber.lmeans foricaiising said brake member to'be rotated by the downwardmovement of said lifting element, and a friction device cooperating withsaid brake member and Ycomprising parts movable' toward and from eachother to control the contact between said friction device and said brakemember, of a single locking member movableinto wedging` engagement withsaid parts to lock said friction device in contact with said brakemember.

Y In a lifting ack, the combination with a lifting element, `means foractuating the same to lift the load, a rotatable brake. member, meansfor causing said brake-member to be rotated by the downward movement ofsaid liftingeleinent, and a friction device cooperating with saidbrake'member and comprising parts movable toward and from each other tocontrol the Contact between said friction device and saidbrake member,of controlling mechanism comprisingl means to normally controlthe actionof said friction device, and a screwY acting on said parts to lock saidfriction device in contact with said bra-ke member.

6. In a lifting jack,-th'e combination with a lifting element7 means foractuating the saine to lift the load,a rotatable brake member, means forcausing said brake inembeito be rotated by the downward movement of saidlifting element, and a friction device cooperating with said brakemember and comprising parts movable toward and from each other tocontrol 'the contact between said friction devicean'd said brakemeinber,

said parts having contact surfaces converging one toward the other, of alocking inembc'r to engage said converging surfaces. anzi lli) means foractuating saidlocking` member I i and holding the saine positively inchagement with said surfaces. Y

l7. vIn a lifting jack, the combi nation with alifting element,r meansfor actuating the same to lift the load, a ro atable brake ineinber7means for causing said b ke member tcbeV rotated by the downwardmovement of said lifting' element, and a friction device cooperatingwith `said brake member to control the downward movement of said.lifting element. of a mechanism to control the action of said frictiondevice on said brake member comprising ay spring to hold the fricn4 tiondevice normally 4in contact with -said brake member, manually operatedmeansto release said brake member, and means other than said spring toretain said friction device in contact with said brake member.

S. In a lifting,lr jack, the combination with a lifting element. meansfor actuating the same, tovlift the load` a rotatable brake member.`means for causing said brake member to be rotated by the downwardmovement of said lifting element, a friction device cooperatingT withsaid brake member to control the downward movement of said lift-ing ele`ment, a spring acting on said friction device to hold the same normallyin contact with said brake member, and manually operated means forreleasing said friction device from the action of said spring. of alocking' devic to positively retain said friction device in contact with.said brake member.

9. in a lifting jack, the combination with a lifting element, means foractuating the same to lift the load, a rotatable brake member, means forcausing said brake member| to be rotated by the downward movement ofsaid lifting element, and a friction device cooperating with said brakemember and comprising parts movable toward and from each other tocontrol the contact between said friction device and said brake member,of a spring acting on said friction device to hold the same normally incontact with said brake member a. manually operated device to releasesaid friction device from the action of said spring, and a screwoperated device to engage said parts and retain said friction device. incontact with said brake member.

10. In a lifting jack, the combination with a lifting clement, means foractuating the same to lift the load, a. rotatable brake member, means`for causing said brake member to be rotated by the downward movement ofsaid lifting element, a friction device comprising contaft membersr toengage said brake. member. and pivoted arms connected with said contact.members to move the same into and out of engagement with said bral-:emember. of a spring actingr on said arms to hold said contact membersnormally in en- `sagement willi said brake member. means to release saidarms from the action of said spring.r a device to engage said arms andpositively retain said contact members in engagement with said brakemember.

1 l. ,in a lifting' ack, the combination with ay liftingT element.ymeans for actuating the same to lift the load. a rotatable brake member,means for causing said brake member to be rotated by the downwardmovement of said lifting` element, and a friction device cooperatingwith said brake member and comprising parts movable toward and from eachother to control the contact between said friction device and said brakemember,

a slide block having a recess provided withA converging walls toengagesaid parts, and a spring acting?r on said slide block to move the sametoward said friction device.

12. In a lifting jack, the combination with a lifting element, means foractuating the same to lift the load, a rotatable brake member, means forcausingr said brake member to be rotated by the downward movement ofsaid lifting element, and a friction device cooperating with said brakemember and comprising parts movable toward and from each other tocontrol the contact between said friction device and said brake member,of a slide block havingr a recess provided with converging walls toengage said parts, a spring1r acting on said slide block to move thesame toward said friction device, and a screw acting on said slide blockto hold the same positively in engagement with said parts of saidfriction device.

13, In a lifting jack, the combination with a liftingr element, meansfor actuating the rame to lift the load, a rotatable brake member. meansfor causing said brake member to be rotated by the downward movement ofsaid lifting' element', and a. friction device having parts movabletoward and from each other to control said brake member, of a slideblock having a tapered recess in one end thereof to receive said partsof said fri c tion device, a stem for said slide block, a spring;racting on said slide block to move the same into engagement with saidparts of said friction device. means for rctracting said slide blockagainst the action of said spring, and a screw threaded plunger movableinto a position toengag/.fe said stem and hold said slide block inengagement with said parts of said friction device.

14. In a mechanism of the character dcscribed, the combination with arotatable brake member, and a friction device to cooperate with saidbrake member, of a spring actingon Said friction device to hold the samenormally in engagement with said brake member. and a screw actuatedmember to positively retain said friction device in engagement with saidbrake member.

15. in a mechanism of the character described, the combination with arotatable brake member.y and a. friction device to cooperate with saidbrake member, of controlline' mechanism comprising manually controlledmeans to normally control thevaction of said friction device, and meansoperable independently of said manually controlled means to positivelyretain said friction device 1n engagement with said brake member.

16. In a mechanism of the character described. tbe combination with arotatable brake member, and a friction device cooperating with saidbrake member and comprisingparts movable toward and from each other tocontrol the contact between said friction device and said brake member,of

lll)

controlling mechanism acting on ysaid parts of said friction device andcomprising means to normally control the action of said friction deviceand other means to lockfsaid friction device. in contact with said brakemember. t

17. In a mechanism of the character described, the combination with arotatable brake member, and a friction device cooperating with saidbrake member and comprising parts movable toward and from each other tocontrol the contact between said friction device and said brake member,of controlling mechanism comprising a device movable into wedgingengagement with said parts, means to lck said device in engagement withsaid parts, andmeans operable independently of the last mentioned meansto normally control the action of said friction device.

18. In a mechanism of the character described, the combination with arotatable brake member and a friction device cooperating with said brakemember and compris-` ing parts movable toward and from each other tocontrol the contact between said friction device and said vbrake member,said parts having contact surfaces converging one toward the other, of alocking member to engage said converging surfaces, and means foractuating said locking member and for holding the same in positiveengagement with said surfaces.`

19. In a mechanism of the character described, the combination with a`rotatable brake member and a friction device cooperating with saidbrake member and comprising parts movable toward and from each other tocontrol the contact between said friction device and said brake member,of a spring actuated device to hold said friction device normally incontact with said brake member, a manually operated device to move saidspring actuated device against the action of its spring to release saidbrake member, and screw operated means to retain saidfriction device incontact with said brake member. Y

20. In a mechanism of the character described, the combination with arotatable brake member and a friction device cooperating withsaid brakemember and comprising parts movable toward and from each other tocontrol the contact between said friction device and said brake member,of a controlling device acting on said movable parts of said frictiondevice to cause the latter to engage said brake member, a spring actingon said controlling device to cause said friction device to be heldnormally in engagement with said brake member, and other means acting onsaid controlling device to positively lock said friction device inengagement with said brake member.

21. In a mechanism of the character described, the combination with arotatable brake member and a friction device cooperating with said brakemember and comprising parts movable toward and from each other tocontrol the contact between said friction device and said brake member.of a slidable member having aA recess to receive said l'parts of saidfriction device and engage thesame with a wedging action, and a springactingon said slidable member tocause the same to move said parts onetoward the other.

22. In a mechanism of the character described, the combination with arotatable brake member and a friction device cooperating with said brakemember and comprising parts movable toward and from `each other tocontrol the contact between said friction device and said brake member,of a slidable member having a recess to receive said parts of saidfriction device and engage the same with a wedging action, a springacting on said slidable member to cause the same to move said parts onetoward the other, and a screw actuated device acting on said slidablemember to cause the same to positively hold said parts against` movementrelatively one to the other.

23. In a mechanism of the character described, the combination with arotatable brake member and a friction device cooperating with said brakemember and comprising parts movable toward and from each other tocontrol the contactfbetween said friction device and'said brake member,of a slide block having a tapered recess in one end thereof `to receivesaid parts `of said friction device, a stem for said slide block, aspring acting on said slide block to move the same into engagement withsaid parts of said friction device, means for retracting said slideblock against the action of said spring, and a screw threaded plungermovable into a position to engage` said stem and hold said slide blockVin engagement with said parts of said friction device.

In testimony whereof, I afiix my signature hereto. a

JAMES C. DAVLEY.

